Whole body hyperthermia is being studied at NIH as a possible means of treatment for cancer. This project includes development of an instrumentation and control system based on utilization of a Tektronix 3l programmable calculator, digital plotter, and interface for data acquisition. The esophageal temperature of the patient is regulated to O.1C accuracy by feedback control of the temperature of water circulating in a set of hyperthermia blankets. The NIH phase of this project was completed August l980, however additional publications have been made.